Magnetic resonance imaging assessment of chemotherapy-related adipocytic maturation in myxoid/round cell liposarcomas: specificity and prognostic value.

OBJECTIVE

To investigate the specificity, clinical implication and prognostic value of MRI adipocytic maturation (MAM) in myxoid/round cells liposarcomas (MRC-LPS) treated with neoadjuvant chemotherapy (NAC).

METHODS

Of the 89 patients diagnosed with MRC-LPS at our sarcoma reference center between 2008 and 2018, 28 were included as they were treated with NAC, surgery and radiotherapy. All patients underwent contrast-enhanced MRIs at baseline and late evaluation. A control cohort of 13 high-grade pleomorphic and dedifferentiated LPS with same inclusion criteria was used to evaluate the specificity of MAM in MRC-LPS. Two radiologists analyzed the occurrence of MAM, changes in the tumor architecture, shape and surrounding tissues during NAC. Pathological features of tumor samples were reviewed and correlated with MRI. Metastatic relapse-free survival was estimated with Kaplan-Meier curves and Cox models. Associations between prognostic T1-based delta-radiomics features and MAM were investigated with Student -test.

RESULTS

MAM was more frequent in MRC-LPS ( = 0.045) and not specific of any type of chemotherapy ( = 0.7). Regarding MRC-LPS, 14 out of 28 patients (50%) demonstrated MAM. Eight patients showed metastatic relapses. MAM was not associated with metastatic relapse-free survival ( = 0.9). MAM correlated strongly with the percentage of histological adipocytic differentiation on surgical specimen ( < 0.001), which still expressed the tumor marker NY-ESO-1. None of the prognostic T1-based delta-radiomics features was associated with MAM.

CONCLUSION

MAM seems a neutral event during NAC.

ADVANCES IN KNOWLEDGE

MAM predominated in MRC-LPS and was not specific of a type of chemotherapy. Occurrence of MAM was not associated with better patients' metastasis free survival.